What Is the Best Method for Foundation Repair? Top Solutions Compared

When your home starts showing signs of trouble-cracks in walls, doors that stick, or floors that slope-you’re not just dealing with an eyesore. You’re facing a structural problem that won’t fix itself. Foundation repair isn’t about aesthetics; it’s about safety, value, and long-term stability. But with so many methods out there, how do you know which one is truly the best?

There’s No One-Size-Fits-All Solution

Many contractors will tell you their method is the best. That’s not helpful. The truth is, the best foundation repair method depends on your home’s age, soil type, climate, and the specific damage you’re seeing. A house built on clay soil in Wellington will behave differently than one on sandy ground in Auckland. What works for a 1950s brick bungalow won’t necessarily work for a modern concrete slab home.

There are five main methods used today. Each has strengths, weaknesses, and ideal use cases. The goal isn’t to pick the most expensive or flashy option-it’s to pick the one that solves your problem without creating new ones.

Pier and Beam: The Gold Standard for Raised Foundations

If your home has a crawl space and wooden floor joists resting on brick piers or concrete footings, you likely have a pier and beam foundation. This is common in older homes in New Zealand, especially those built before the 1980s.

The repair method here involves installing steel or concrete piers beneath the existing ones to lift and stabilize the structure. Steel piers are driven deep-often 10 to 20 feet-until they reach stable soil or bedrock. This transfers the weight of the house away from weak, shifting soil.

Why it works: It’s durable, adjustable, and doesn’t require tearing up your floor. It also allows access to plumbing and wiring under the house. In Wellington, where wet winters cause clay soils to expand and contract, pier and beam systems are often the most reliable long-term fix.

Downside: It’s not cheap. Costs range from $5,000 to $20,000 depending on the number of piers needed. But compared to the cost of a collapsed floor or cracked chimney, it’s a smart investment.

Helical Piers: For Tough Soil and Heavy Loads

Helical piers look like giant screws made of steel. They’re twisted into the ground using hydraulic equipment until they reach load-bearing soil. Once in place, brackets connect them to your foundation, lifting and holding it steady.

This method shines in areas with poor soil conditions-like expansive clays or loose fill. It’s also ideal for homes with limited access, such as narrow side yards or tight urban lots. Because they’re installed with torque, contractors can measure exactly how much load each pier is carrying. That means you know it’s working, not just guessing.

Real-world example: A 1970s home in Lower Hutt had a 4-inch slope across the living room. After installing 12 helical piers, the foundation was lifted back to level within two days. No demolition. No mess. No need to move out.

Cost: $1,500 to $3,000 per pier. Most homes need 6 to 15 piers. It’s more expensive than slab jacking but far more permanent.

Slab Jacking: Quick Fix for Concrete Slabs

If your home has a concrete slab foundation-common in homes built from the 1980s onward-slab jacking might be your go-to. This method involves drilling small holes (about 1 inch) through the slab and injecting a grout mixture underneath. The pressure lifts the sunken concrete back into place.

Modern slab jacking uses polyurethane foam instead of traditional cement grout. The foam expands quickly, cures in minutes, and weighs far less than concrete slurry. That means less stress on the soil and faster results.

Pros: Fast. Clean. Usually done in a single day. Costs between $500 and $1,500 per section. Great for small areas like a garage floor or a single room.

Cons: It’s a temporary fix if the soil underneath hasn’t been stabilized. If the ground keeps shifting, the slab will sink again. This method doesn’t address the root cause-it just masks the symptom.

Best for: Minor settling, not major structural failure. If your slab is cracked all the way through or shifting more than 2 inches, slab jacking alone won’t cut it.

Concrete Underpinning: For Severe Structural Damage

This is the heavy-duty option. Underpinning means extending the foundation deeper by pouring new concrete footings beneath the existing ones. It’s often used when the original foundation was too shallow or built on unstable ground.

In New Zealand, underpinning is common after earthquakes or in areas with high water tables. It’s the only method that permanently replaces or reinforces the foundation’s base.

It’s messy, loud, and takes weeks. You’ll likely need to vacate part of your home. Costs can hit $30,000 or more.

But here’s the thing: if your foundation is crumbling, your walls are bowing, or your floors are sagging more than 3 inches, underpinning is often the only way to save the structure. It’s not glamorous, but it’s the most thorough solution.

Foundation Crack Repair: Don’t Ignore the Small Stuff

Not every foundation problem needs a full repair job. Hairline cracks in concrete slabs are common, especially in newer homes. These are usually caused by normal curing shrinkage and aren’t structural.

But if a crack is wider than 1/8 inch, runs diagonally, or is getting wider over time-that’s a red flag. Epoxy injection is the standard fix. The epoxy is forced into the crack under pressure, bonding the concrete back together and preventing water from seeping in.

For wider cracks, carbon fiber straps can be applied to the wall’s surface. They’re invisible once painted over and add tensile strength without adding bulk. This method is used in basements and retaining walls where space is tight.

Cost: $300 to $1,200 per crack. Quick, affordable, and often enough to prevent bigger problems down the line.

What’s the Best Method? It Depends on These 4 Factors

Before you sign a contract, ask these questions:

1. What’s your soil type? Clay expands when wet and shrinks when dry. Sandy soil drains well but can wash away. Silt is unstable. A soil test costs $200-$400 but saves you thousands in the wrong repair.
2. How old is your home? Older homes often have shallow footings. Newer homes may have slab foundations. The repair must match the original design.
3. How bad is the damage? A 1-inch slope? Slab jacking or piering. A 4-inch slope and cracked walls? Underpinning or helical piers.
4. What’s your budget and timeline? Slab jacking is fast and cheap. Underpinning is slow and expensive. Choose based on your priorities, not just the contractor’s pitch.

Don’t let a contractor rush you. Get at least two written estimates. Ask to see photos of past jobs-especially ones done in your area. Ask if they use licensed engineers for design. In New Zealand, reputable companies always involve structural engineers for major repairs.

Red Flags to Watch Out For

Some contractors will push the most expensive option because they make more money. Others will downplay the problem to get the job fast. Here’s what to avoid:

• “We can fix it with sealant.” (Cracks need structural repair, not paint.)
• “No need for a soil test.” (That’s like fixing a car without checking the engine.)
• “We’ve done 100 of these.” (Ask for references and photos from the last 3 jobs.)
• “Pay half upfront.” (Reputable companies require only a small deposit, often 10% or less.)

Always check if the company is registered with the New Zealand Building Practitioners Board. Look for certifications from the Foundation Repair Association or the International Association of Foundation Repair Contractors.

What Happens If You Do Nothing?

Foundations don’t heal. They don’t stop moving. They don’t get better with time.

Left unchecked, a small crack becomes a wide gap. A slightly sloping floor becomes a tripping hazard. A sticking door becomes a warped frame. Water seeps in, mold grows, and your home’s value drops.

Insurance won’t cover foundation damage from gradual settling. You’ll pay out of pocket-and the cost doubles every year you wait.

Next Steps: What to Do Right Now

1. Take photos of all cracks, gaps, and uneven floors. Note where they are and how wide they are.

2. Check your gutters and downspouts. Are they directing water away from the house? Poor drainage is the #1 cause of foundation problems.

3. Call two licensed foundation specialists. Ask for a free inspection and written report. Don’t accept verbal estimates.

4. Ask for a soil test if the damage is more than minor. It’s not optional-it’s essential.

5. Don’t rush. A good repair takes planning. A bad repair costs more to fix later.